The invention relates to a belt tensioner for seat belt systems in vehicles, especially to an end fitting tensioner.
Belt tensioners for seat belt systems are generally known already from automotive engineering. In so-called end fitting tensioners in the case of activation of the belt tensioner the actually fixed end of a webbing usually connected to the seat frame or the vehicle body is tightened in order to provide for tensioning of the entire webbing. In the state of the art both linearly operating as well as rotatory end fitting tensioners are described. In the rotatory end fitting tensioners the webbing end is connected to a belt shaft which is driven upon activation of the belt tensioner so as to wind webbing onto the belt shaft.
For the assembly of the seat belt system, especially in respect of end fitting tensioners increasingly a process is desired in which the webbing end is secured to the belt tensioner only after the belt tensioner has been mounted on the vehicle body or on the seat frame.
In order to permit said subsequent securing of the webbing, DE 103 13 551 B3 suggests a seat belt retractor in which a hollow belt shaft pivoted in the belt shaft housing includes an end-side aperture and an axially aligned belt shaft slit. Moreover, in a housing leg of the belt shaft housing a feed-through slit is further provided so that the end of the webbing formed as end loop can be introduced into the hollow belt shaft in the axial direction together with a belt pin inserted in the end loop and can be fixed there.
Such subsequent arrangement of the webbing at the belt shaft requires considerable space in the axial direction, however, which is not always provided in the area of an already mounted end fitting tensioner. Consequently, in cramped space conditions the suggested securing of the webbing end to the belt shaft is not possible or only possible with great assembly efforts. In addition, due to said frequently cramped space conditions in the area of the end fitting tensioner an especially compact tensioner design is generally desirable.
Hence it is the object of the invention to provide a compact belt tensioner in which especially the end of a webbing can be subsequently secured to a belt shaft of the rotatory belt tensioner with little assembly effort.